QuakeScout
Magnitude4.3

Reviewed by USGSTonga20y ago

M4.3 earthquake 174 km WNW of Neiafu, Tonga

Sunday, July 9, 2006, 19:16:06 UTC · 18.099°S, 175.527°W

A magnitude 4.3 earthquake struck 174 km WNW of Neiafu, Tonga on Sunday, July 9, 2006, 19:16:06 UTC, at a depth of 80.5 km (intermediate).

Magnitude
4.3
Light · mb
Depth
81 km
Intermediate
Felt reports
0
Did You Feel It?
Est. shaking
—
No ShakeMap
PAGER alert
None
Not issued
Tsunami
No flag
USGS feed

Outlined circle: this earthquakeDashed circle: 50 km aftershock search area

In context

How big was it, and why here?

Energy released

43 tons of TNT

That is about 1/354 of the Hiroshima bomb. A magnitude 5.0 releases about 11 times more energy.

Tectonic setting

78 km

from the nearest mapped plate boundary, between the Tonga and Niuafo'ou plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: intermediate

81 km

Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.

Did You Feel It?

Where it was felt

No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.

I felt it — report to USGS ↗

USGS PAGER estimate

Who was exposed to shaking

USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.

After the main event

Aftershocks within 50 km

USGS lists 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M4.5 on July 17, 2006. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M41h6h1d3d7d14d30dMainshock M4.3
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 4.5138 km WNW of Neiafu, Tonga20y ago · 44 km E of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 1,198 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 8.0TongaJanuary 4, 1903 · 219 km S of this epicenter
  2. 8.02006 Tonga EarthquakeMay 3, 2006 · 275 km SE of this epicenter
  3. 7.8159 km W of Pangai, TongaDecember 14, 1950 · 182 km S of this epicenter
  4. 7.4103 km ESE of Neiafu, TongaFebruary 27, 1921 · 277 km E of this epicenter
  5. 7.385 km ESE of Neiafu, TongaJanuary 2, 1907 · 258 km SE of this epicenter
  6. 7.2108 km SE of Neiafu, TongaDecember 19, 1906 · 280 km SE of this epicenter
  7. 7.2241 km WNW of Houma, TongaAugust 21, 1911 · 280 km SW of this epicenter
  8. 7.2Fiji regionMarch 31, 1907 · 151 km W of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 8 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

  1. 1865M8.0

    Tonga Islands

    18 Nov 1865 · 264 km away

    Limited damage (under $1M)tsunami

  2. 2006M7.9

    Tonga Islands

    3 May 2006 · 275 km away · intensity VII

    Limited damage (under $1M)tsunami

  3. 1903M8.0

    Tonga Islands

    4 Jan 1903 · 219 km away

  4. 1902M7.8

    Tonga Islands

    9 Feb 1902 · 265 km away

  5. 1950M7.7

    Tonga Islands

    14 Dec 1950 · 164 km away · intensity VI

  6. 1913M7.6

    Tonga Islands

    26 Jun 1913 · 265 km away

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers

Closest city pages